Re: Hide an image inside an image

On Sat, 13 Dec 2008 13:29:18 +0000, rich wrote:

On Sat, 13 Dec 2008 12:42:45 +0000, rich wrote:

On Sat, 13 Dec 2008 12:45:17 +0100, Fr@nk Stef@ni wrote:

poncho schrieb:
Hi,
I hope I can correctly describe what I would like to do.

I want to merge image A into image B. If you look at the result you
will only see image B.
But if you use a colored filter (e.g. a red foil/filter or red
glasses) you will see image A into image B.

Maybe you remember some kind of paper copy protection from computer
games 20 years ago.
They had some kind of printed copy protection where you need to input
some code into the game
to proceed. Some printed protection where only visible with a red
film.

How can I do something like that with gimp?

Look for the steganography plugin.

HTH,
Frank

As I read the OP its not about encryption ie. hiding one file inside
another.

Its more along the lines of the colour blindness test cards where some
images are not visible because the viewer cannot see red or green etc.

I would think that I you took an image that is predominantly blue and
green then added the "code" in red you would get something like the OP
requires. Needs some experimentation I think.

Just a very quick test
I took a standard ishihara chart added a couple of semi-opaque layers.
the result is here
http://rapidshare.com/files/172974974/test.xcf

If you toggle the first layer on and off, replicating looking through a
filter then you should see a result. Needs a lot more experimenting.

* * *
Rich,

I would think this is a simple form of steganography, using a single
color filter for a coding/decoding device...

JR the postman
.

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